The present invention relates to improvements in pipe line suspension means, and in particular to a new and improved spring-loaded hanger assembly for supporting a section of a pipe line.
Where long pipe lines are supported along their lengths from an overhead support, they are subjected to large variations in temperature through the fluid flowing therethrough, as well as external influences which cause the pipe to elongate or contract, sway, sag or otherwise move relative to the supporting structure. Such movement is dangerous, in that it tends to impose an undue strain on the pipe line, particularly where fixed and rigid supports are provided. Consequently, it is customary to provide spring-loaded support structures including an internal spring which is adapted to resist vertical movement of the supported pipe, or in extreme cases to adjust the position of the supporting structure to compensate for deflection or movement of the pipe with a cushioning action.
In conventional pipe hangers of the aforementioned type, an upper plate is slidably mounted within a housing and a coiled compression spring is seated at its upper end on the upper plate, and at its lower end is seated upon a bottom plate which is secured to the bottom end of the casing by welding or by bolting. Since such pipe hangers are being used to support pipe lines in a corrosive atmosphere to an increasing extent, it is desirable to coat the compression spring with a protective coating and to galvanize the metal housing, as well as all the other parts, in order to protect these parts from corrosion or other damage due to environmental conditions. However, when the bottom plate is welded to the housing as the final step in assembling the hanger unit, the heat of the welding operation melts the protective coating on the spring portion adjacent the weld, and further destroys the galvanizing on the adjacent surfaces on the housing. In addition, many of the finished housings contain springs of different strengths and cross-sections, and one housing may hold a variety of different springs. Furthermore, if the bottom plate is bolted on, additional materials and additional assembly steps are required. In addition, the plate and the housing require opposed annular shoulders to accommodate the bolts and nuts.
An object of the present invention is to overcome the aforementioned difficulty by providing an improved variable spring hanger assembly in which the bottom plate is not welded to the housing and therefore the unit is not subjected to such heat as to adversely affect the spring coating or the housing wall galvanization.
Another object of the invention is the provision of a spring hanger assembly of the character described in which the bottom or lower plate is securely mounted in positions by means of fingers extending outwardly from the circumference thereof engaging bayonet slots in the lower end portion of the housing.
Still another object of the invention is the provision of a spring hanger assembly of the character described which is of a simple construction which renders it more easy to coat and to galvanize, the assembly being economical to manufacture.
Yet a further object of the invention is to provide a series of partial annular grooves within the bottom plate to allow insertion of the tool further compressing the spring and allowing easy rotation of the lower plate into engagement with the blind slot of the bayonet slot.
A further object of the invention is the provision of a spring hanger assembly of the character described which may be assembled in an extremely easy and rapid operation, and in which the housing is so arranged that it may be used interchangeably to contain springs of various sizes and shapes, so that only one type of housing need be stocked in inventory.